Devices and methods for optical communication in a rotary platform

ABSTRACT

In one example, a device includes a first platform having a first side and a second platform having a second side that overlaps the first side. The device also includes an actuator that rotates the first platform relative to the second platform. The device also includes a plurality of light sources mounted to the first platform in a substantially circular arrangement around the axis of rotation of the first platform. The plurality of light sources emit a plurality of light beams such that respective adjacent light beams intersect at least at a predetermined distance to the first side. The first side remains at least at the predetermined distance to the second side in response to the actuator rotating the first platform. The device also includes a light detector mounted to the second platform and positioned to at least partially overlap at least one of the plurality of light beams.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/283,328 filed Oct. 1, 2016, the entire contents of which areincorporated herein by reference as if fully set forth in thisapplication.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

Rotary joint devices are often used for transmission of power and/orelectrical signals between one structure and another structure in anelectromechanical system that operates by causing a relative rotationbetween the two structures (e.g., stator and rotor). Example systemsthat employ rotary joint devices include remote sensing systems (e.g.,RADARs, LIDARs, etc.) and robotic systems (e.g., for directingmicrophones, speakers, robotic components, etc.), among others.

SUMMARY

In one example, a device comprises a first platform that includes afirst mounting surface. The device also comprises a second platform thatincludes a second mounting surface positioned within a predetermineddistance to the first mounting surface. The device also comprises anactuator that rotates the first platform relative to the second platformabout an axis of rotation of the first platform. The first mountingsurface remains within a predetermined distance to the second mountingsurface in response to the actuator rotating the first platform. Thedevice also comprises a plurality of light sources mounted on the firstmounting surface in a circular arrangement around the axis of rotation.The plurality of light sources emit a plurality of light beams thatdiverge to form a ring-shaped light beam incident on the second mountingsurface. The device also comprises a light detector mounted on thesecond mounting surface such that the light detector remains at leastpartially overlapping the ring-shaped light beam in response to theactuator rotating the first platform.

In another example, a device includes a first platform having a firstside and a second platform having a second side positioned to overlapthe first side of the first platform. The device also includes anactuator that rotates the first platform relative to the second platformand about an axis of rotation of the first platform. The device alsoincludes a plurality of light sources mounted to the first platform in asubstantially circular arrangement around the axis of rotation of thefirst platform. The plurality of light sources emit a plurality ofdiverging light beams such that respective adjacent light beamsintersect at least at a predetermined distance to the first side. Thefirst side remains at least at the predetermined distance to the secondside in response to the actuator rotating the first platform. The devicealso includes a light detector mounted to the second platform andpositioned to at least partially overlap at least one of the pluralityof light beams.

In yet another example, a device includes a first platform and a secondplatform positioned to overlap the first platform. The device alsoincludes an actuator that rotates the first platform relative to thesecond platform and about an axis of rotation of the first platform. Thefirst platform remains at a predetermined distance to the secondplatform in response to the actuator rotating the first platform. Thedevice also includes at least one light source mounted to the firstplatform. The at least one light source provides a ring-shaped lightbeam incident on the second platform. The device also includes a lightdetector mounted to the second platform and positioned to remain atleast partially overlapping the ring-shaped light beam in response tothe actuator rotating the first platform.

These as well as other aspects, advantages, and alternatives, willbecome apparent to those of ordinary skill in the art by reading thefollowing detailed description, with reference where appropriate to theaccompanying figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a vehicle, according to an example embodiment.

FIG. 2 is a simplified block diagram of a vehicle, according to anexample embodiment.

FIG. 3 is a simplified block diagram of a device that includes a rotaryjoint, according to an example embodiment.

FIG. 4A illustrates a side view of a device that includes a rotaryjoint, according to an example embodiment.

FIG. 4B illustrates a cross-section view of the device shown in FIG. 4A.

FIG. 4C illustrates another cross-section view of the device shown inFIG. 4A.

FIG. 5 is a flowchart of a method, according to an example embodiment.

DETAILED DESCRIPTION

The following detailed description describes various features andfunctions of the disclosed implementations with reference to theaccompanying figures. In the figures, similar symbols identify similarcomponents, unless context dictates otherwise. The illustrativeimplementations described herein are not meant to be limiting. It may bereadily understood by those skilled in the art that certain aspects ofthe disclosed implementations can be arranged and combined in a widevariety of different configurations.

I. Overview

An example rotary joint device includes two platforms arranged such thata first side of a first platform remains within a predetermined distanceto a second side of a second platform in response to a relative rotationbetween the two platforms. For instance, the two platforms may includecircularly shaped disks arranged concentrically about a common axis ofthe respective disks to maintain an overlap between the two respectivesides separated by the predetermined distance in response to rotation ofany of the two platforms about the common axis. Other configurations arepossible as well.

In some implementations, the first platform may include a plurality oflight sources in a substantially circular arrangement around an axis ofrotation of the first platform. For example, the light sources could beimplemented as light emitting diodes (LEDs) mounted on a printed circuitboard (PCB) that is included in the first platform. The plurality oflight sources may emit a plurality of light beams toward the secondplatform. For instance, the light beams may diverge and intersect toform a ring-shaped light beam incident on the second platform. Further,in these implementations, the second platform may include a lightdetector that remains at least partially overlapping the ring-shapedlight beam in response to a rotation of the first platform relative tothe second platform.

With this arrangement, for instance, the rotary joint device can providean optical communication path for transmitting signals from the firstplatform to the second platform. By way of example, the device mayinclude a first controller that provides a modulated electrical signalfor modulating the plurality of light beams emitted by the plurality oflight sources of the first platform. For instance, the modulatedelectrical signal may indicate sensor data collected by a sensor mountedin the first platform. Further, the device may include a secondcontroller coupled to the light detector of the second platform. Thesecond controller could thus receive an indication of modulated lightdetected by the light detector, and use the received indication as abasis for determining the sensor data transmitted via the firstcontroller.

In some configurations, a signal-to-noise ratio of the modulated signaldetected by the light detector may be affected by the rotation of thefirst platform. For instance, an intensity of light beam(s) incident onthe light detector could vary due to fluctuations in the distancebetween the two platforms caused by the rotation and/or characteristicsof the light sources (e.g., beam divergence characteristics, separationdistance between adjacent light sources, etc.), among other factors. Asa result, an output of the light detector may similarly vary.

To improve the signal-to-noise ratio, in some implementations, thesecond platform may also include a second light detector that alsoremains at least partially overlapping the light beam(s) incident on thesecond platform in response to the rotation of the first platform. Forinstance, the two light detectors can be arranged along a circular paththat is concentric with the circular arrangement of the light sources(e.g., around the axis of rotation). In this instance, both lightdetectors could (at least partially) remain along a propagation path ofone or more of the light beams emitted by the light sources of the firstplatform as the first platform rotates. Further, in some examples, thetwo light detectors can be arranged according to an expected variationin the light intensity of the incident light beams. By way of example, afirst separation distance between the two light detectors can beselected to be less than a second separation distance between adjacentlight sources of the first platform.

With this arrangement, for instance, when the first light detector isaligned with a first light source (e.g., maximum signal-to-noise ratio),the second light detector may become aligned between the first lightsource and a second light source. As the first platform rotates, the twolight detectors may become less aligned (i.e., reduced signal-to-noiseratio) with the first light source, but one or both of the two lightdetectors may simultaneously become more aligned with the second lightsource. Thus, the combined outputs of the two light detectors mayexperience less rotation-dependent fluctuations (i.e., improvedsignal-to-noise ratio) as compared to an output of only one of the twolight detectors. Accordingly, in some implementations, the device or acomponent thereof (e.g., second controller) could determine anindication of modulated light incident on the second platform based on asum of the outputs of the two light detectors (e.g., a sum of electricalcurrents associated with the two light detectors). For instance, the sumof the electrical currents can be computed by a controller coupled toboth light detectors or can be provided by coupling the two lightdetectors in a parallel circuit configuration, among otherpossibilities. Thus, with this arrangement for instance, the rotaryjoint device can improve reliability and/or communication bandwidthbetween the two platforms.

In some implementations, the second platform may also include aplurality of light sources and one or more light detectors that aresimilar, respectively, to the light sources and detector(s) of the firstplatform. Thus, for instance, the rotary joint device may supporttwo-way communication between the first platform and the secondplatform.

Additionally, in some implementations, modulated light emitted by therespective light sources of the two platforms can be modulated based ona controller access network (CAN) bus protocol. For example, the firstcontroller of the first platform can cause the light sources of thefirst platform to emit one or more light pulses indicating an assertionof a dominant (high priority) state for transmitting data toward thesecond platform. Upon detecting the assertion message, the secondcontroller of the second platform can stop or delay transmitting datausing the light sources of the second platform until the first platformcompletes transmission of the higher priority data. Similarly, forexample, the second controller can assert the dominant state fortransmitting data toward the first platform.

Further, in some examples, the rotary joint device could facilitateoptical CAN bus communication between multiple CAN nodes (e.g., sensors,computing systems, subsystems, etc.) distributed between the firstplatform and the second platform. For example, the first controller canassign different priorities to data originating from one or more sensorsmounted in the first platform. Further, for example, the secondcontroller can assign different priorities for data originating from oneor more systems or subsystems (e.g., navigation system, user interfacesystem, etc.) coupled to the second controller. In these examples, oneor both of the two controllers can then buffer, schedule, prioritize,and/or otherwise allocate time blocks for transmitting various blocks ofdata between the two platforms according to respective determined orassigned priorities associated with the communicated data.

Other example arrangements, configurations, and operations are possibleas well and are described in greater detail within exemplaryimplementations herein.

II. Example Electromechanical Systems and Devices

Systems and devices in which example embodiments may be implemented willnow be described in greater detail. In general, the embodimentsdisclosed herein can be used with any electromechanical system thatincludes a moveable component. An example system can provide fortransmission of power and/or signals between the moveable component andother parts of the system. Illustrative embodiments described hereininclude vehicles that have moveable components such as sensors andwheels that communicate with other components of the vehicle and/or withone another. However, an example electromechanical system may also beimplemented in or take the form of other devices, such as sensingplatforms (e.g., RADAR platforms, LIDAR platforms, directional sensingplatforms, etc.), robotic devices, industrial systems (e.g., assemblylines, etc.), medical devices (e.g., medical imaging devices, etc.), ormobile communication systems, among others.

The term “vehicle” is broadly construed herein to cover any movingobject, including, for instance, an aerial vehicle, watercraft,spacecraft, a car, a truck, a van, a semi-trailer truck, a motorcycle, agolf cart, an off-road vehicle, a warehouse transport vehicle, a farmvehicle, or a carrier that rides on a track (e.g., roller coaster,trolley, tram, train car, etc.), among other examples.

FIG. 1 illustrates a vehicle 100, according to an example embodiment. Inparticular, FIG. 1 shows a Right Side View, Front View, Back View, andTop View of the vehicle 100. Although vehicle 100 is illustrated in FIG.1 as a car, as noted above, other types of vehicles are possible aswell. Furthermore, although vehicle 100 can be configured to operateautonomously, the embodiments described herein are also applicable tovehicles that are not configured to operate autonomously or that areconfigured to operate semi-autonomously. Thus, vehicle 100 is not meantto be limiting. As shown, vehicle 100 includes five sensor units 102,104, 106, 108, and 110, and four wheels, exemplified by wheel 112.

In some embodiments, sensor units 102-110 may include any combination ofsensors, such as global positioning system sensors, inertial measurementunits, radio detection and ranging (RADAR) units, cameras, laserrangefinders, light detection and ranging (LIDAR) units, or acousticsensors, among other possibilities.

As shown, sensor unit 102 is mounted to a top side of the vehicle 100opposite to a bottom side of the vehicle 100 where the wheel 112 ismounted. Further, sensor units 104-110 are respectively mounted torespective sides of vehicle 100 other than the top side. As shown,sensor unit 104 is positioned at a front side of vehicle 100, sensor 106is positioned at a back side of vehicle 100, the sensor unit 108 ispositioned at a right side of vehicle 100, and sensor unit 110 ispositioned at a left side of vehicle 100.

Although sensor units 102-110 are shown to be mounted in particularlocations on vehicle 100, in some embodiments, sensor units 102-110 canbe mounted in other locations, either inside or outside vehicle 100. Forexample, although sensor unit 108 as shown is mounted to a rear-viewmirror of vehicle 100, sensor unit 108 may alternatively be positionedin another location along the right side of vehicle 100. Further, whilefive sensor units are shown, in some embodiments more or fewer sensorunits may be included in vehicle 100. However, for the sake of example,sensor units 102-110 are positioned as shown.

In some embodiments, one or more of sensor units 102-110 may include oneor more movable mounts on which the sensors can be movably mounted. Amovable mount may include, for example, a rotating platform.Alternatively or additionally, a movable mount may include a tiltingplatform. Sensors mounted on a tilting platform could be tilted within agiven range of angles and/or azimuths, for example. A movable mount maytake other forms as well.

In some embodiments, one or more of sensor units 102-110 may include oneor more actuators configured to adjust a position and/or orientation ofsensors in the sensor unit by moving the sensors and/or movable mounts.Example actuators include motors, pneumatic actuators, hydraulicpistons, relays, solenoids, and piezoelectric actuators, among others.

As shown, vehicle 100 includes one or more wheels such as wheel 112 thatare configured to rotate to cause the vehicle to travel along a drivingsurface. In some embodiments, wheel 112 may include at least one tirecoupled to a rim of wheel 112. To this end, wheel 112 may include anycombination of metal and rubber, or a combination of other materials.Vehicle 100 may include one or more other components in addition to orinstead of those shown.

FIG. 2 is a simplified block diagram of a vehicle 200, according to anexample embodiment. Vehicle 200 may be similar to vehicle 100, forexample. As shown, vehicle 200 includes a propulsion system 202, asensor system 204, a control system 206, peripherals 208, and a computersystem 210. In other embodiments, vehicle 200 may include more, fewer,or different systems, and each system may include more, fewer, ordifferent components. Further, the systems and components shown may becombined or divided in any number of ways.

Propulsion system 202 may be configured to provide powered motion forthe vehicle 200. As shown, propulsion system 202 includes anengine/motor 218, an energy source 220, a transmission 222, andwheels/tires 224.

Engine/motor 218 may be or include any combination of an internalcombustion engine, an electric motor, a steam engine, and a Stirlingengine. Other motors and engines are possible as well. In someembodiments, propulsion system 202 may include multiple types of enginesand/or motors. For instance, a gas-electric hybrid car may include agasoline engine and an electric motor. Other examples are possible.

Energy source 220 may be a source of energy that powers the engine/motor218 in full or in part. That is, engine/motor 218 may be configured toconvert energy source 220 into mechanical energy. Examples of energysources 220 include gasoline, diesel, propane, other compressedgas-based fuels, ethanol, solar panels, batteries, and other sources ofelectrical power. Energy source(s) 220 may additionally or alternativelyinclude any combination of fuel tanks, batteries, capacitors, and/orflywheels. In some embodiments, energy source 220 may provide energy forother systems of vehicle 200 as well.

Transmission 222 may be configured to transmit mechanical power fromengine/motor 218 to wheels/tires 224. To this end, transmission 222 mayinclude a gearbox, clutch, differential, drive shafts, and/or otherelements. In embodiments where transmission 222 includes drive shafts,the drive shafts may include one or more axles that are configured to becoupled to wheels/tires 224.

Wheels/tires 224 of vehicle 200 may be configured in various formats,including a unicycle, bicycle/motorcycle, tricycle, or car/truckfour-wheel format. Other wheel/tire formats are possible as well, suchas those including six or more wheels. In any case, wheels/tires 224 maybe configured to rotate differentially with respect to otherwheels/tires 224. In some embodiments, wheels/tires 224 may include atleast one wheel that is fixedly attached to transmission 222 and atleast one tire coupled to a rim of the wheel that could make contactwith a driving surface. Wheels/tires 224 may include any combination ofmetal and rubber, or combination of other materials. Propulsion system202 may additionally or alternatively include components other thanthose shown.

Sensor system 204 may include any number of sensors configured to senseinformation about vehicle 200 and/or an environment in which vehicle 200is located, as well as one or more actuators 236 configured to modify aposition and/or orientation of the sensors. As shown, sensor system 204includes a Global Positioning System (GPS) 226, an inertial measurementunit (IMU) 228, a RADAR unit 230, a laser rangefinder and/or LIDAR unit232, and a camera 234. Sensor system 204 may include additional sensorsas well, including, for example, sensors that monitor internal systemsof vehicle 200 (e.g., an O₂ monitor, a fuel gauge, an engine oiltemperature, etc.). Other sensors are possible as well. In someexamples, sensor system 204 may be implemented as multiple sensor unitseach mounted to the vehicle in a respective position (e.g., top side,bottom side, front side, back side, right side, left side, etc.).

GPS 226 may include any sensor (e.g., location sensor) configured toestimate a geographic location of vehicle 200. To this end, for example,GPS 226 may include a transceiver configured to estimate a position ofvehicle 200 with respect to the Earth. IMU 228 may include anycombination of direction sensors configured to sense position andorientation changes of the vehicle 200 based on inertial acceleration.Example IMU sensors include accelerometers, gyroscopes, other directionsensers, etc. RADAR unit 230 may include any sensor configured to senseobjects in an environment in which vehicle 200 is located using radiosignals. In some embodiments, in addition to sensing the objects, RADARunit 230 may be configured to sense the speed and/or heading of theobjects.

Laser rangefinder or LIDAR unit 232 may include any sensor configured tosense objects in the environment in which vehicle 200 is located usinglight. In particular, laser rangefinder or LIDAR unit 232 may includeone or more light sources configured to emit one or more beams of lightand a detector configured to detect reflections of the one or more beamsof light. Laser rangefinder or LIDAR 232 may be configured to operate ina coherent (e.g., using heterodyne detection) or an incoherent detectionmode. In some examples, LIDAR unit 232 may include multiple LIDARs, witheach LIDAR having a particular position and/or configuration suitablefor scanning a particular region of an environment around vehicle 200.

Camera 234 may include any camera (e.g., still camera, video camera,etc.) configured to capture images of the environment in which vehicle200 is located. Sensor system 204 may additionally or alternativelyinclude components other than those shown. Actuator(s) 236 may includeany type of actuator configured to adjust a position, orientation,and/or pointing direction of one or more of the sensors in sensor system204. Example actuators include motors, pneumatic actuators, hydraulicpistons, relays, solenoids, and piezoelectric actuators, among otherexamples.

Control system 206 may be configured to control operation of vehicle 200and/or components thereof. To this end, control system 206 may include asteering unit 238, a throttle 240, a brake unit 242, a sensor fusionalgorithm 244, a computer vision system 246, a navigation or pathingsystem 248, and an obstacle avoidance system 250.

Steering unit 238 may be any combination of mechanisms configured toadjust the heading of vehicle 200. Throttle 240 may be any combinationof mechanisms configured to control the operating speed of engine/motor218 and, in turn, the speed of vehicle 200. Brake unit 242 may be anycombination of mechanisms configured to decelerate vehicle 200. Forexample, brake unit 242 may use friction to slow wheels/tires 224. Insome examples, brake unit 242 may also convert kinetic energy ofwheels/tires 224 to an electric current.

Sensor fusion algorithm 244 may be an algorithm (or a computer programproduct storing an algorithm) configured to accept data from sensorsystem 204 as an input. The data may include, for example, datarepresenting information sensed at the sensors of sensor system 204.Sensor fusion algorithm 244 may include, for example, a Kalman filter, aBayesian network, an algorithm for some of the functions of the methodsherein, or any other algorithm. Sensor fusion algorithm 244 may furtherbe configured to provide various assessments based on the data fromsensor system 204, including, for example, evaluations of individualobjects and/or features in the environment in which vehicle 100 islocated, evaluations of particular situations, and/or evaluations ofpossible impacts based on particular situations.

Computer vision system 246 may be any system configured to process andanalyze images captured by camera 234 in order to identify objectsand/or features in the environment in which vehicle 200 is located,including, for example, traffic signals and obstacles. To this end,computer vision system 246 may use an object recognition algorithm, aStructure from Motion (SFM) algorithm, video tracking, or other computervision techniques. In some embodiments, computer vision system 246 mayadditionally be configured to map the environment, track objects,estimate the speed of objects, etc.

Navigation and pathing system 248 may be any system configured todetermine a driving path for vehicle 200. Navigation and pathing system248 may additionally be configured to update the driving pathdynamically while vehicle 200 is in operation. In some embodiments,navigation and pathing system 248 may be configured to incorporate datafrom sensor fusion algorithm 244, GPS 226, LIDAR unit 232, and one ormore predetermined maps so as to determine the driving path for vehicle200. Obstacle avoidance system 250 may be any system configured toidentify, evaluate, and avoid or otherwise negotiate obstacles in theenvironment in which vehicle 200 is located. Control system 206 mayadditionally or alternatively include components other than those shown.

Peripherals 208 (e.g., input interface, output interface, etc.) may beconfigured to allow vehicle 200 to interact with external sensors, othervehicles, external computing devices, and/or a user. To this end,peripherals 208 may include, for example, a wireless communicationsystem 252, a touchscreen 254, a microphone 256, and/or a speaker 258.

Wireless communication system 252 may be any system configured towirelessly couple to one or more other vehicles, sensors, or otherentities, either directly or via a communication network. To this end,wireless communication system 252 may include an antenna and a chipsetfor communicating with the other vehicles, sensors, servers, or otherentities either directly or via a communication network. Chipset orwireless communication system 252 in general may be arranged tocommunicate according to one or more types of wireless communication(e.g., protocols) such as Bluetooth, communication protocols describedin IEEE 802.11 (including any IEEE 802.11 revisions), cellulartechnology (such as GSM, CDMA, UMTS, EV-DO, WiMAX, or LTE), Zigbee,dedicated short range communications (DSRC), and radio frequencyidentification (RFID) communications, among other possibilities.Wireless communication system 252 may take other forms as well.

Touchscreen 254 may be used by a user as an input interface to inputcommands to vehicle 200. To this end, touchscreen 254 may be configuredto sense at least one of a position and a movement of a user's fingervia capacitive sensing, resistance sensing, or a surface acoustic waveprocess, among other possibilities. Touchscreen 254 may be capable ofsensing finger movement in a direction parallel or planar to thetouchscreen surface, in a direction normal to the touchscreen surface,or both, and may also be capable of sensing a level of pressure appliedto the touchscreen surface. Touchscreen 254 may be formed of one or moretranslucent or transparent insulating layers and one or more translucentor transparent conducting layers. Touchscreen 254 may take other formsas well.

Microphone 256 may be configured to receive audio (e.g., a voice commandor other audio input) from a user of vehicle 200. Similarly, speakers258 may be configured to output audio to the user of vehicle 200.Peripherals 208 may additionally or alternatively include componentsother than those shown.

Computer system 210 may be configured to transmit data to, receive datafrom, interact with, and/or control one or more of propulsion system202, sensor system 204, control system 206, and peripherals 208. To thisend, computer system 210 may be communicatively linked to one or more ofpropulsion system 202, sensor system 204, control system 206, andperipherals 208 by a system bus, network, and/or other connectionmechanism (not shown).

In one example, computer system 210 may be configured to controloperation of transmission 222 to improve fuel efficiency. As anotherexample, computer system 210 may be configured to cause camera 234 tocapture images of the environment. As yet another example, computersystem 210 may be configured to store and execute instructionscorresponding to sensor fusion algorithm 244. Other examples arepossible as well.

As shown, computer system 210 includes processor 212 and data storage214. Processor 212 may comprise one or more general-purpose processorsand/or one or more special-purpose processors. To the extent processor212 includes more than one processor, such processors could workseparately or in combination. Data storage 214, in turn, may compriseone or more volatile and/or one or more non-volatile storage components,such as optical, magnetic, and/or organic storage among otherpossibilities, and data storage 214 may be integrated in whole or inpart with processor 212.

In some embodiments, data storage 214 contains instructions 216 (e.g.,program logic) executable by processor 212 to execute various vehiclefunctions. Data storage 214 may contain additional instructions as well,including instructions to transmit data to, receive data from, interactwith, and/or control one or more of propulsion system 202, sensor system204, control system 206, and/or peripherals 208. In some embodiments,data storage 214 also contains calibration data for one or more of thesensors in sensor system 204. For example, the calibration data mayinclude a mapping between previously obtained sensor measurements andone or more predetermined inputs to the sensors. Computer system 210 mayadditionally or alternatively include components other than those shown.

Power supply 260 may be configured to provide power to some or all ofthe components of vehicle 200. To this end, power supply 260 mayinclude, for example, a rechargeable lithium-ion or lead-acid battery.In some embodiments, one or more banks of batteries could be configuredto provide electrical power. Other power supply materials andconfigurations are possible as well. In some embodiments, power supply260 and energy source 220 may be implemented together as one component,as in some all-electric cars for instance.

In some embodiments, vehicle 200 may include one or more elements inaddition to or instead of those shown. For example, vehicle 200 mayinclude one or more additional interfaces and/or power supplies. Otheradditional components are possible as well. In such embodiments, datastorage 214 may further include instructions executable by processor 212to control and/or communicate with the additional components. Stillfurther, while each of the components and systems are shown to beintegrated in vehicle 200, in some embodiments, one or more componentsor systems can be removably mounted on or otherwise connected(mechanically or electrically) to vehicle 200 using wired or wirelessconnections.

III. Example Rotary Joint Configurations

Within examples, a rotary joint may be configured as a communicationinterface between two structures of an electromechanical system, inwhich one or both of the two structures is configured to rotate orotherwise move relative to the other structure. To that end, in someimplementations herein, a portion of the rotary joint (e.g., rotor) maybe coupled to one structure of the example system and another portion(e.g., stator) may be coupled to the other structure of the examplesystem. Additionally or alternatively, in some example implementations,the rotary joint may be included within a structure arranged between twostructures that rotate (or move) with respect to one another. Forinstance, in an example system that includes a robotic joint thatcouples two robotic links, the rotary joint may be disposed between thetwo robotic links. Other example implementations are possible as well.

FIG. 3 is a simplified block diagram of a device 300 that includes arotary joint, according to an example embodiment. For example, device300 can be used with an electromechanical system, such as any ofvehicles 100 and 200, or any other electromechanical system. Thus, forinstance, device 300 can be physically implemented as a rotary jointthat facilitates communication between two moveable components of asystem (or subsystem), such as a rotating platform mounts sensors suchas any of the sensors included in sensor units 102, 104, 106, 108, 110,sensor system 204, among other possibilities. As shown, device 300includes an actuator 302, a first platform 310 and a second platform340.

Actuator 302 may be similar to the actuator(s) 236 of the vehicle 200.In some examples, actuator 302 may be configured to cause a relativerotation between first platform 310 (or one or more components thereof)and second platform 340 (or one or more components thereof). To thatend, for example, the actuator 302 may be coupled to one or both ofplatforms 310, 340 (or one or more components thereof) to cause therelative rotation.

First platform 310 may comprise or may be coupled to a sensor mountingplatform, and may be configured as a rotor or a stator in a rotary jointconfiguration. For example, actuator 302 may be configured to rotateplatform 310 relative to platform 340 and about an axis of rotation ofplatform 310 (e.g., rotor axis, etc.). Alternatively or additionally,for example, actuator 302 could rotate platform 340 relative platform310 about an axis of rotation of platform 340. Thus, within variousexamples, platform 310 can be configured as a rotating platform (e.g.,rotor) or a stationary platform (e.g., stator) in a rotary jointconfiguration.

As shown, platform 310 includes a sensor 312, a first controller 314,one or more light sources 316, one or more optical elements 318, and oneor more light detectors 330. In some examples, platform 310 may compriseany solid material suitable for supporting and/or mounting variouscomponents of platform 310. For instance, platform 310 may include aprinted circuit board (PCB) that mounts light source(s) 316, lightdetector(s) 320, and/or other components of platform 310. The PCB inthis instance can be positioned such that the mounted components arealong a side of platform 310 facing or opposite to a corresponding sideof platform 340. With this arrangement, for instance, light source(s)316 can emit light 360 for propagation toward second platform 340 andlight detector(s) 330 can receive light 380 propagating from secondplatform 340 toward first platform 310.

Sensor 312 may include any combination of sensors mounted to firstplatform 310, such as one or more sensors of sensor system 204, one ormore of the sensors included in vehicle 100, and/or any other sensorthat can be mounted on platform 310. A non-exhaustive list of examplesensors may include direction sensors (e.g., gyroscopes), remote sensingsensors (e.g., RADARs, LIDARs, etc.), sound sensors (e.g., microphones),among others.

First controller 314 may be configured to operate one or more of thevarious components of first platform 310. To that end, controller 314may include any combination of general-purpose processors,special-purpose-processors, data storage, logic circuitry, and/or anyother circuitry configured to operate one or more components of device300. In one implementation, similarly to computing system 210,controller 314 includes one or more processors (e.g., processor 212)that execute instructions (e.g., instructions 216) stored in datastorage (e.g., data storage 214) to operate sensor 312 and/or lightsource(s) 316. In another implementation, controller 314 alternativelyor additionally includes circuitry wired to perform one or more of thefunctions and processes described herein. For example, in any of theseimplementations, first controller 314 can be configured to receivesensor data collected by sensor 312 and to provide a modulatedelectrical signal indicative of the sensor data to light source(s) 316.For instance, the sensor data may indicate a measured direction ororientation of sensor 312, a scan of a surrounding environment by sensor312, sounds detected by sensor 312, and/or any other sensor output ofsensor 312.

Light source(s) 316 may include one or more light sources arranged toemit or otherwise provide light beam(s) 360 incident on second platform340. To that end, light source(s) 316 may include laser diodes, lightemitting diodes (LEDs), vertical cavity surface emitting lasers (VCSEL),organic light emitting diodes (OLEDs), polymer light emitting diodes(PLED), light emitting polymers (LEP), liquid crystal displays (LCD),microelectromechanical systems (MEMS), discharge light sources (e.g.,fluorescent lamp, etc.), incandescent light sources (e.g., halogen lamp,filament lamp, etc.), combustion light sources, and/or any other lightsource configured to emit light 360 toward platform 340.

In a first implementation, light source(s) 316 comprise a plurality oflight sources mounted in platform 310 in a substantially circulararrangement around an axis of rotation of the platform 310. Theplurality of light sources may emit a plurality of light beams thatdiverge to form a ring-shaped light beam incident on platform 340(and/or a component thereof). For example, platforms 310 and 340 can bepositioned at a predetermined distance to one another. The predetermineddistance can be selected according to the respective distances betweenadjacent light sources and/or beam divergences of the adjacent lightsources. A beam divergence may be an angular measure of the increase inbeam diameter or radius relative to a distance of propagation of lightbeam(s) 360. Thus, for instance, the predetermined distance can beselected to be greater than or equal to a distance at which adjacentlight beams of light 360 intersect (after emission by respective lightsources 316). In a second implementation, light source(s) 316 comprise asingle ring-shaped light source. For instance, a single light source 316can be implemented as an OLED patterned on a PCB surface in the shape ofa ring, among other possibilities. In a third implementation, lightsource(s) 316 comprise one or more light sources coupled to one or moreoptical elements (e.g., light diffusers, lens, filters, etc.) that arearranged to redirect or focus light beam(s) 360 to form a ring-shapedlight beam incident on platform 340.

Accordingly, in some examples, device 300 can optionally include one ormore optical elements 318 (e.g., light diffuser, ring diffuser, etc.)optically coupled to light source(s) 316 to condition and/or focus light304 to form a ring-shaped light beam.

Detector(s) 330 may comprise one or more light detectors orphotodetectors that convert light 380 (propagating from platform 340toward platform 310) into a signal (e.g., a voltage and/or currentsignal) that can be measured via first controller 314. To that end,light detector(s) or photodetector(s) 330 may include any combination oflight sensors such as photodiodes, photoemission sensors, photoelectricsensors, photovoltaic sensors, thermal sensors, polarization sensors,and/or photochemical sensors, among others. In some examples,detector(s) 330 may be configured to detect light at a particularwavelength or within a particular bandwidth associated with light 380.Thus, for example, device 300 can be less sensitive to noise (e.g.,environmental light signals) that is not within a predeterminedwavelength range associated with light 380.

In some implementations, detector(s) 330 comprise a detector thatremains at least partially overlapping light beam 380 in response toactuator 302 rotating platform 310 relative to platform 340. Forexample, light beam 380 may comprise light beam(s) having a ring shapeor other continuous shape (e.g., a combination of adjacent light beamsthat intersect at or prior to arrival at platform 310, etc.) extendingaround an axis of rotation of platform 310. In this example, detector330 can be positioned at a particular distance to the axis of rotationsuch that detector 330 overlaps (at least partially) light beam(s) 380at any orientation of platform 310 about the axis of rotation. Thus, forexample, where light beam 380 is a modulated light beam (e.g., sequenceof light pulses, etc.) indicating wirelessly transmitted data fromplatform 340, detector 330 can continue to detect the modulated lightbeam even if platform 310 rotates relative to platform 340.

In some scenarios, where light 380 comprises a plurality of light beamsfrom a plurality of light sources, the intensity of light 380 arrivingat platform 310 may vary at different orientations or positions ofplatform 310 about an axis of rotation thereof. As a result, asignal-to-noise ratio of output from a single detector may varydepending on the orientation of the first platform 310 about the axis.

Accordingly, in some implementations, detector(s) 330 comprise aplurality of detectors that remain at least partially overlapping lightbeam 380 in response to actuator 302 rotating platform 310 relative toplatform 340. For example, a first detector can be positioned at anoffset separation distance to a second detector such that when the firstdetector detects a high intensity portion of light 380, the seconddetector detects a lower intensity portion of light 380, and vice versa.In these implementations, controller 314 can use a sum of output signalsfrom the two detectors (e.g., the two detectors can be coupled in aparallel circuit configuration, or the output signals from the twodetectors can be summed at controller 314, etc.) as a light detectionsignal that is less susceptible to noise fluctuations (e.g., improvedsignal-to-noise ratio, etc.) due to the orientation of first platform310 about the axis of rotation.

Second platform 340 may be configured as a rotor platform or a statorplatform, similarly to the various configurations discussed above forplatform 310. As shown, platform 340 includes a second controller 344,one or more light sources 346, one or more optical elements 348, and oneor more light detectors 350. In some examples, platform 340 may alsoinclude one or more orientation sensors (not shown), such as encoders,range sensors, etc., that provide a measure of the orientation of firstplatform 310 relative to second platform 340 (and about an axis ofrotation of first platform 310).

Second controller 344 can have various physical implementations (e.g.,processors, logic circuitry, data storage, etc.) similarly to firstcontroller 314, for example. Further, controller 344 can operate lightsource(s) 346 to transmit a modulated light signal 380 indicating atransmission of data or instructions similarly to, respectively,controller 314, light source(s) 316, and light signal 360. For instance,second controller 344 can provide a modulated electrical signal to causelight source(s) 346 to provide modulated light 380 indicatinginstructions for operating sensor 312 and/or any other component (e.g.,actuator 302, etc.) that may be coupled to platform 310. Further, forinstance, controller 344 can receive a modulated electrical signal fromdetector(s) 350 in response to detection of modulated light 360. To thatend, for instance, modulated light 360 may indicate sensor datacollected by sensor 312 and transmitted, via light 360, to platform 340.

Thus, for example, light source(s) 346, optical element(s) 348, andlight detector(s) 350 can be configured, physically implemented, and/orarranged, etc., in a similar manner to, respectively, light source(s)316, optical element(s) 318, and light detector(s) 330. However, in someexamples, one or more components of platform 340 can have differentcharacteristics than corresponding components of platform 310. Forexample, light source(s) 346 can be physically implemented to include adifferent number of light sources or may emit light 380 having differentwavelengths than wavelengths of light 360, among other possibilities(e.g., different phases, polarizations, intensities, etc.).

In some implementations, device 300 may include fewer components thanthose shown. For example, device 300 can be implemented without opticalelement(s) 318, optical element(s) 348, and/or any other componentshown. In some implementations, device 300 may include one or morecomponents in addition to or instead of those shown. For example,platforms 310 and/or 340 may include additional or alternative sensors(e.g., microphone 256, etc.), computing subsystems (e.g., navigationsystem 248, etc.), communication interfaces (e.g., wirelesscommunication system 252, etc.), and/or any other component such as anyof the components of vehicles 100 and 200. Thus, in some examples,device 300 can facilitate one way or two way communication between anynumber of devices (respectively distributed or coupled to platforms 310and 340) via an optical communication path defined by light signals 360,380. For instance, controllers 314 and 344 can operate the opticalcommunication path as a shared data bus by scheduling/controlling datatraffic between component(s) mounted (or coupled) to platform 310 andcomponent(s) mounted (or coupled) to platform 340.

Accordingly, in some examples, device 300 can be configured to support acontroller area network (CAN) data bus communication protocol forcommunication between subsystems or CAN nodes in a system such asvehicles 100 and 200. In one example arrangement, each of controllers314 and 344 may include or may be coupled to a respective CANtransceiver that transmits (e.g., “CAN_TX”) and/or monitors modulatedelectrical signals that are used to modulate, respectively, light beams360 and 380. Further, the respective CAN transceivers can also receive(e.g., “CAN_RX”) and/or monitor outputs detected, respectively, bydetectors 330 and 350. By way of example, when data associated with afirst CAN node (e.g., sensor 312) is being transmitted (e.g., bymodulating light 350 using CAN_TX signal of platform 310) from platform310, the CAN transceiver of platform 310 can simultaneously monitor itsCAN_RX signal. If the monitored CAN_RX signal matches the CAN_TX signal,then controller 314 may continue transmitting the data from the firstCAN node. Whereas, if there is a mismatch, then controller 314 maydetermine that a second CAN node associated with platform 340 has ahigher priority or dominant state for using the CAN data bus, and maythus stop or delay transmitting additional data from the first CAN nodeuntil the transmission of the data from the second CAN node iscompleted.

Thus, with this arrangement, for instance, controllers 314, 344, and/oranother computing system (e.g., computing system 210, etc.) can assignor determine transmission priorities for the various CAN nodescommunicating over optical communication interface 360, 380. When a CANnode asserts a dominant state for communication over the CAN bus,controllers 314 and/or 344 can responsively delay, buffer, and/orotherwise re-schedule data from other CAN nodes until the dominant CANnode completes its transmission. By way of example, if transmission ofdata from sensor 312 is assigned a higher priority than data or sensoroperation instructions from controller 344, then controller 314 maycause light source(s) 316 to modulate light 360 in a manner thatindicates that data from sensor 312 has the dominant transmission state.For example, modulated light signal 360 may cause the CAN_RX signal ofcontroller 344 to correspond to a logical low value. In response todetecting a low CAN_RX value, for instance, controller 344 may beconfigured to stop or delay transmission of data using light 380 untiltransmission of the data associated with sensor 312 is completed, oruntil data associated with another CAN node coupled to controller 344and having a higher priority than the CAN node of sensor 312 becomesavailable. If higher priority data is available for transmission, thencontroller 344 can operate light source(s) 346 to modulate light 380according to a modulation indicating an assertion of the dominant statefor data transmission by controller 344 instead of the data transmissionby controller 314, for example.

The assignment of transmission priorities to data associated withvarious CAN nodes can be based on various factors depending on thedesign and application of the system that includes device 300. In oneexample, where sensor 312 is a direction sensor (e.g., gyroscope), thesystem can assign a high priority to data from sensor 312 when thesensor detects at least a threshold amount of change to the measureddirection, and a lower priority when the sensor detects less than thethreshold amount of change (e.g., fluctuations). The threshold can beany value depending on design considerations and/or outputcharacteristics of sensor 312 among other factors. Additionally, otherCAN transmission priority assignment schemes are possible as well.Additionally, other CAN protocol implementations are possible as well.Thus, within examples, device 300 provides an optical rotary joint CANbus communication interface.

FIG. 4A illustrates a side view of a device 400 that includes a rotaryjoint, according to an example embodiment. For example, device 400 maybe similar to device 300, and can be used with an electromechanicalsystem such as vehicles 100 and 200. As shown, device 400 includesplatforms 410 and 440 that may be similar, respectively, to platforms310 and 340. Further, as shown, device 400 also includes a plurality oflight sources 412, 414, 416, 418 that may be similar to light source(s)316. Further, as shown, device 400 includes light detectors 450 and 452that may be similar to detector(s) 350. In the example shown, a side 410a of platform 410 is positioned at a predetermined distance 404 to aside 440 a of platform 440.

It is noted that some components of device 400 are omitted from theillustration of FIG. 4A for convenience in description. For example,FIGS. 4B and 4C illustrate cross-section views of device 400.

In the cross section view shown in FIG. 4B, side 410 a of platform 410is pointing out of the page. As shown in FIG. 4B, device 400 alsoincludes detectors 430, 432 that may be similar to detector(s) 330, forexample. Further, as shown, device 400 also includes light sources 420,422, 424, 426, 428 that are arranged (along with light sources 412-418)in a substantially circular arrangement around axis of rotation 402 ofplatform 410.

In the cross section view shown in FIG. 4C, side 440 a of platform 440is pointing out of the page. As shown in FIG. 4C, device 400 may alsoinclude a plurality of light sources, exemplified by light sources 444and 446, which are also arranged in a circular arrangement around axisof rotation 402. Thus, in some examples, similarly to device 300, device400 can be configured for two-way communication between platforms 410and 440. For instance, light sources 412-428 of platform 410 can beconfigured to emit light propagating toward detectors 450 and/or 452 ofplatform 440. Similarly, for instance, light sources of platform 440(e.g., light sources 444, 446, etc.) can be configured to emit lightpropagating toward detectors 430 and/or 432 of platform 410.

Referring back to FIG. 4A, light sources 412, 414, 416, 418 mayrespectively emit a plurality of light beams 462 (extending betweenarrows 462 a and 462 b), 464 (extending between arrows 464 a and 464 b),466 (extending between arrows 466 a and 466 b), and 468 (extendingbetween arrows 468 a and 468 b). Further, as shown, adjacent light beamsmay intersect at or prior to arrival of the respective light beams atside 440 a (and/or detectors 450, 452) of platform 440 to form acombined (e.g., continuous, etc.) light beam. As shown in FIG. 4B, forinstance, light sources 420, 422, 424, 426, 428 can also emit lightbeams that intersect with respective adjacent light beams, similarly tolight beams 462-468 emitted by light sources 412-418. As shown in FIG.4C, for instance, light beams 470, 472, 474, 476, 478 that arrive atplatform 440 may correspond, respectively, to light beams emitted bylight sources 420, 422, 424, 426, 428. Together, for instance, lightbeams 462-478 may combine prior to propagation for predetermineddistance 404 from platform 410 to form a continuous ring-shaped lightbeam extending around axis of rotation 402 as shown in FIG. 4C.

Thus, in line with the discussion above, detectors 450 and/or 452 maycontinue to receive the combined light beam as platforms 410 and/or 440rotate with respect to one another (e.g., about axis of rotation 402).By way of example, platform 410 and/or 440 can be rotated such thatfirst side 410 a and second side 440 a remain within predetermineddistance 404 to one another. For instance, platform 410 could be rotatedabout the shared (e.g., center) axis 402, thereby substantiallyremaining at least at predetermined distance 404 to platform 440. Tothat end, distance 404 could be any distance suitable for communicationbetween one or more of light sources 412-428 and one or more ofdetectors 450, 452.

For instance, as shown in FIG. 4A, distance 404 can be selected to begreater than a distance at which adjacent light beams of light beams462, 464, 466, 468 intersect. Alternatively, in another implementation(not shown), distance 404 can be selected to be equal to the distance atwhich the adjacent light beams intersect. With either arrangement, theintersecting light beams can form a continuous or combined light beamincident on side 440 a such that detector 450 (and/or 452) can remainoverlapping the incident combined light beam as platform 410 rotatesabout axis 402.

The distance at which adjacent light beams intersect, for instance, maydepend on respective beam divergences of the adjacent light beams. Thebeam divergence of light beam 462, for instance, may correspond to theangle between arrows 462 a and 462 b and may be based on physicalcharacteristics or a configuration of light source 412. For example, ifthe beam divergence of light beam 462 increases, then the distance (fromside 410 a) at which arrow 462 b intersects with arrow 464 a maydecrease, and vice versa. Additionally or alternatively, for instance,the distance at which the adjacent light beams intersect may depend on aseparation distance between adjacent light sources. For instance, if theseparation distance between light sources 412 and 414 increases, thenthe distance (from side 410 a) at which arrows 462 b and 464 a intersectmay also increase. Accordingly, predetermined distance 404 can be basedon an arrangement (e.g., separation distances) and/or beam divergencecharacteristics of light sources 412-428. Thus, in some examples,distance 404 can be adjusted by using fewer, more, or different lightsources (e.g., having different beam divergences) than those shown, inaccordance with various applications (e.g., size requirements, etc.) ofdevice 400.

Additionally or alternatively, in some examples, detectors 450 and/or452 could be configured to remain overlapping the combined light beam inresponse to a different type of relative motion (e.g., other than arotation) between platforms 410 and 440 even if the motion causes achange to distance 404. By way of example, an actuator (not shown) ofdevice 400 could be configured to adjust the position of platform 410along a translational path (e.g., along axis 402, along another linearaxis, etc.), or other path (e.g., elliptical path, curved path, etc.).For instance, device 400 may be included in a computer numeric control(CNC) machine or a 3D printer that operates a tool (e.g., drill, saw,printer head, etc.) via a robotic arm or other hardware component. Inthis instance, platform 410 may be coupled to the tool, and platform 440may be coupled to a controller (and/or an actuator) that adjusts theposition of platform 410 linearly along axis 402. In this instance,device 400 may be configured to restrict linear motion of platform 410along axis 402 such that distance 404 remains sufficiently large forbeams 462-468 to intersect prior to arrival of beams 462-468 at secondside 440 a (or detectors 450/462). Thus, for example, detectors 450and/or 452 may continue to receive the combined light beam as platforms410 and/or 440 are linearly (or otherwise) displaced with respect to oneanother.

Although sides 410 a and 440 a are shown to be substantially paralleland overlapping, in some examples, device 400 can be alternativelyarranged such that platforms 410 and 440 are not substantially paralleland/or overlapping. By way of example, platform 410 can be alternativelyarranged at a different angle (e.g., tilted, etc.) relative to platform440, and device 400 may include a mirror (e.g., optical element 318,etc.) that reflects light beams 462-468 (prior to or after intersectionof the light beams) toward side 440 a of platform 440 (and/or towarddetectors 450/452). In one example implementation, platform 410 may beincluded in a robotic link (not shown) configured to move along oraround multiple axes of motion (not shown), and platform 440 may beincluded in a robotic joint coupled to the robotic link. In thisimplementation, device 400 may include one or more optical elements(e.g., mirrors) arranged such that light beams 462-468 are reflected orotherwise directed toward side 440 a (or detectors 450, 452) in responseto a motion of the robotic link according to any of the axes of motion.Thus, in this implementation, detectors 450 and/or 452 could remainoverlapping the combined light beam 462-468 in response to variousmotions of the platform 410 relative to platform 440.

As noted above, in some scenarios, an output signal from detector 450and/or 452 may vary as platform 410 rotates about axis 402. Referringback to FIG. 4A by way of example, consider a scenario where platform410 rotates about axis 402 in a clockwise direction. In the scenario,detector 450 could be implemented as a photodiode (or otherphotodetector) that outputs an electrical current having an amplitudethat varies based on the intensity of detected light (e.g., light beam464). As platform 410 rotates, light beam 464 emitted by light source414 may away from detector 450 (e.g., toward left side of the page), andthus the intensity of light beam 464 may also become reduced.Additionally, after a sufficient amount of rotation detector 452 mayoverlap a region where light beams 464 and 466 (emitted by source 416)intersect, such as the region shown to overlap detector 452. In thisscenario, the light intensity detected by detector 450 may thus increasedue to detecting light from both sources 414 and 416.

Thus, to mitigate the noise effect of such variations, as noted abovefor device 300, device 400 could sum the output signals of detectors 450and 452 to generate a less angle dependent output signal (e.g., anoutput signal that is less dependent on the position of platform 410relative to platform 440). Continuing with the scenario above by way ofexample, when detector 450 overlaps the high light intensity area thatpreviously overlapped detector 452, detector 452 will then overlap a lowlight intensity area of light beam 466 (e.g., where light beam 466 doesnot intersect with light beams 464 and/or 468). Thus, with thisarrangement, a sum of signals from detectors 450 and 452 may remainrelatively more stable than a signal from only one of the two detectors.

To facilitate this, in some implementations, detectors 450 and 452 canbe arranged along a circular path that is concentric with the circulararrangement of light sources 412-428. For example, as shown in FIG. 4C,detectors 450 and 452 are both at a substantially similar given distanceto axis of rotation 402. Although FIG. 4C shows detectors 450 and 452positioned at the given distance to axis 402 that is greater than adistance between light sources 412-428 and axis 402, in someimplementations, detectors 450 and 452 can be alternatively arranged atthe same distance as the circular arrangement of light sources 412-428(e.g., between light sources 444 and 446, etc.), or at a lesser distanceto axis 402.

Further, in some implementations, a separation distance betweendetectors 450 and 452 can be selected to be less than a separationdistance between adjacent light sources of platform 410. For instance,as shown in FIG. 4A, the separation distance between detectors 450 and452 is less than the separation distance between light sources 414 and416. Thus, for instance, when detector 450 overlaps a region where lightbeams 464 and 466 do not intersect, detector 452 simultaneously overlapsa region where both light beams intersect. Conversely, for instance,when detector 450 overlaps the intersecting light beam region, thendetector 452 may overlap a non-intersecting region (e.g., of light beam466).

It is noted that device 400 may include fewer or more components thanthose shown, such as any of the components of device 300 (e.g.,actuators, sensors, controllers, etc.), among other possibilities. Inone example, although device 400 is shown to include nine light sourcesmounted on each platform, device 400 can alternatively include more orfewer light sources. In another example, light sources 412-418 can bereplaced with a single ring-shaped light source extending around axis402 to provide a continuous (ring-shaped) light beam around axis 402. Inyet another example, one or more light sources can be optically coupledto a light diffuser that redirects and/or focuses light from the lightsource(s) to form a ring-shaped light beam incident on platform 440.

It is also noted that the shapes, dimensions, and relative positionsshown in FIGS. 4A-4C for device 400 and/or the various componentsthereof are not necessarily to scale and are only illustrated as shownfor convenience in description. Thus, in some implementations, device400 and/or one or more components thereof can have other forms, shapes,arrangements, and/or dimensions as well.

IV. Example Methods and Computer-Readable Media

FIG. 5 is a flowchart of a method 500, according to an exampleembodiment. Method 500 shown in FIG. 5 presents an embodiment of amethod that could be used with any of the vehicles 100, 200, and/or thedevices 300, 400, for example. Method 500 may include one or moreoperations, functions, or actions as illustrated by one or more ofblocks 502-506. Although the blocks are illustrated in a sequentialorder, these blocks may in some instances be performed in parallel,and/or in a different order than those described herein. Also, thevarious blocks may be combined into fewer blocks, divided intoadditional blocks, and/or removed based upon the desired implementation.

In addition, for method 500 and other processes and methods disclosedherein, the flowchart shows functionality and operation of one possibleimplementation of present embodiments. In this regard, each block mayrepresent a module, a segment, a portion of a manufacturing or operationprocess, or a portion of program code, which includes one or moreinstructions executable by a processor for implementing specific logicalfunctions or steps in the process. The program code may be stored on anytype of computer readable medium, for example, such as a storage deviceincluding a disk or hard drive. The computer readable medium may includenon-transitory computer readable medium, for example, such ascomputer-readable media that stores data for short periods of time likeregister memory, processor cache and Random Access Memory (RAM). Thecomputer readable medium may also include non-transitory media, such assecondary or persistent long term storage, like read only memory (ROM),optical or magnetic disks, compact-disc read only memory (CD-ROM), forexample. The computer readable media may also be any other volatile ornon-volatile storage systems. The computer readable medium may beconsidered a computer readable storage medium, for example, or atangible storage device.

In addition, for method 500 and other processes and methods disclosedherein, each block in FIG. 5 may represent circuitry that is wired toperform the specific logical functions in the process.

At block 502, method 500 involves modulating light emitted by one ormore light sources mounted to a first platform. For example, controller314 can receive sensor data collected by sensor 312, and provide amodulated electrical signal to cause light source(s) 316 to emitmodulated light, such as a sequence of light pulses or a light intensitymodulated light signal. The modulated light, for example, may beindicative of the sensor data collected by sensor 312.

At block 504, method 500 involves rotating the first platform relativeto the second platform. The second platform may include one or morelight detectors arranged to remain at least partially overlapping lightfrom the one or more light sources in response to the rotation. Forexample, device 400 can rotate platform 410 about a common axisextending through centers of platforms 410 and 440. As a result, forinstance, platforms 410 and 440 may remain at least at predetermineddistance 404 to one another. Further, detector 450 and/or 452 can bearranged along a circular path as shown in FIG. 4C such that thedetector(s) 450, 452 remain at least partially overlapping one or moreof light beams 462-478 emitted respectively by light sources 412-428.

At block 506, method 500 involves using output from the one or morelight detectors to determine data indicated by the modulated lightemitted by the one or more light sources. In some examples, device 400can sum the signals from detectors 450, 452 and use the combined signalas a basis to determine the modulated electrical signal transmitted vialight beams 462-478. Device 400 can then use the modulated electricalsignal as a basis to determine data transmitted from platform 410 toplatform 440.

It should be understood that arrangements described herein are forpurposes of example only. As such, those skilled in the art willappreciate that other arrangements and other elements (e.g. machines,interfaces, functions, orders, and groupings of functions, etc.) can beused instead, and some elements may be omitted altogether according tothe desired results. Further, many of the elements that are describedare functional entities that may be implemented as discrete ordistributed components or in conjunction with other components, in anysuitable combination and location, or other structural elementsdescribed as independent structures may be combined.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims, along with the full scope ofequivalents to which such claims are entitled. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting.

What is claimed is:
 1. A system comprising: a first platform thatincludes a first mounting surface; a second platform that includes asecond mounting surface; an actuator configured to rotate the firstplatform about an axis of rotation of the first platform; a plurality oflight sources mounted on the first mounting surface, wherein theplurality of light sources are configured to emit a plurality of lightbeams that diverge to form a ring-shaped light beam projected onto thesecond mounting surface; a light detector mounted on the second mountingsurface such that the light detector remains at least partiallyoverlapping the ring-shaped light beam in response to the actuatorrotating the first platform; a device coupled to the first platform; anda controller configured to: receive data from the device, modulate anelectrical signal based on the received data to form a modulatedelectrical signal, and cause transmission of the modulated electricalsignal for receipt by the plurality of light sources, wherein theplurality of light sources modulate the ring-shaped light beam based onthe modulated electrical signal.
 2. The system of claim 1, wherein thedevice comprises a sensor mounted on the first platform such that thesensor rotates in response to the actuator rotating the first platform,and wherein the data received by the controller comprises sensor datacollected using the sensor.
 3. The system of claim 1, wherein thecontroller is configured to determine a transmission priority for thedata from the device, and wherein the controller is configured tomodulate the modulated electrical signal further based on the determinedtransmission priority.
 4. The system of claim 1, wherein the controlleris a first controller, the system further comprising: a secondcontroller configured to: (i) receive an indication of the modulatedring-shaped light beam from the light detector and (ii) determine thedata from the device based on at least the received indication of themodulated ring-shaped light beam.
 5. The system of claim 4, wherein thedata from the device is first data, wherein the second controller isconfigured to receive second data for transmission to the firstcontroller, and wherein the first controller is configured to delaytransmission of the modulated electrical signal for receipt by theplurality of light sources based on a first transmission priority of thefirst data being less than a second transmission priority of theoperation second data.
 6. The system of claim 5, wherein the firstcontroller is configured to determine the first transmission priority.7. The system of claim 5, wherein the second controller is configured todetermine the second transmission priority.
 8. The system of claim 1,wherein the plurality of light sources are mounted in a circulararrangement around the axis of rotation of the first platform.
 9. Thesystem of claim 1, wherein the controller is configured to modulate themodulated electrical signal according to a controller access network(CAN) bus protocol.
 10. The system of claim 1, wherein the firstmounting surface remains within a given distance to the second mountingsurface in response to the actuator rotating the first platform.
 11. Thesystem of claim 1, wherein the light detector is a first light detector,the system further comprising: a second light detector mounted on thesecond mounting surface such that the second light detector remains atleast partially overlapping the ring-shaped light beam in response tothe actuator rotating the first platform.
 12. The system of claim 11,wherein the first light detector is at a given distance to the axis ofrotation, and wherein the second light detector is at the given distanceto the axis of rotation.
 13. The system of claim 11, wherein the firstlight detector is electrically coupled to the second light detector in aparallel circuit configuration.
 14. The system of claim 11, wherein thefirst light detector is at a first separation distance to the secondlight detector, and wherein the first separation distance is less than asecond separation distance between two adjacent light sources of theplurality of light sources.
 15. A device comprising: a first platformhaving a first side; a second platform having a second side positionedto overlap the first side of the first platform; an actuator configuredto rotate the first platform about an axis of rotation of the firstplatform; a plurality of light sources mounted to the first side of thefirst platform, wherein the plurality of light sources are configured toemit a plurality of diverging light beams toward the second side of thesecond platform, wherein each diverging light beam of the plurality ofdiverging light beams intersects two respective diverging light beams ofthe plurality of diverging light beams; a light detector mounted to thesecond platform and positioned to at least partially overlap at leastone of the plurality of diverging light beams; a controller configuredto cause transmission of a modulated electrical signal for receipt bythe plurality of light sources, wherein the plurality of light sourcesmodulate the plurality of diverging light beams based on the modulatedelectrical signal; and a device coupled to the first platform, whereinthe controller is configured to: (i) receive data from the device and(ii) modulate the modulated electrical signal based on the receiveddata.
 16. The device of claim 15, wherein the plurality of light sourcescomprise light emitting diodes (LEDs).
 17. The device of claim 15,wherein the plurality of light sources are mounted on a first printedcircuit board (PCB) included in the first platform, and wherein thelight detector is mounted on a second PCB included in the secondplatform.
 18. A method comprising: receiving data from a device mountedto a first platform; modulating an electrical signal based on thereceived data by a controller; transmitting the modulated electricalsignal for receipt by a plurality of light sources mounted on a firstmounting surface of the first platform; rotating the first platformabout an axis of rotation of the first platform; emitting a plurality oflight beams from the plurality of light sources toward a second mountingsurface of a second platform, wherein the plurality of light beamsdiverge to form a ring-shaped light beam projected onto the secondmounting surface and extending around the axis of rotation, and whereinthe plurality of light sources modulate the ring-shaped light beam basedon the modulated electrical signal; and detecting the ring-shaped lightbeam at a light detector mounted on the second mounting surface, whereinthe light detector remains at least partially overlapping thering-shaped light beam during the rotation of the first platform aboutthe axis of rotation.